Tert-butyl peroxybenzoate-doped spiro-OMeTAD for perovskite solar cells with efficiency over 23%

Perovskite solar cells (PSCs) have made great strides as new generation photovoltaic technology. The hole transport materials (HTMs) play an indispensable part in high performing PSCs. Spiro-OMeTAD (Spiro) is the most frequently used HTM. However, pristine Spiro has low conductivity and poor hole mobility. Additives engineering is considered as an effective strategy to solve the dilemma. Here, an organic peroxide additive tert-butyl peroxybenzoate (TBPB) is introduced into Spiro. TBPB not only promotes the rapid oxidation of Spiro to generate more carriers, but also tunes the HOMO of Spiro to achieve proper energy level matching with perovskite layer. Consequently, the TBPB modified device achieves a power conversion efficiency (PCE) of 23.45% with high fill factor (FF) of 81.97%. Meanwhile, the modification of TBPB improves the hysteresis effect, reproducibility and environmental stability of the device. After 80 days of storage in ambient air (RH 26%), the TBPB-doped unencapsulated PSCs still maintained 88.8% of their initial efficiency.

Automated summary

Perovskite solar cells have made great progress as a new generation photovoltaic technology. Researchers introduced an organic peroxide additive, TBPB, into a commonly used hole transport material, Spiro, to improve the performance and stability of the cells.